Kawasaki Ki-100

[pampa14]

I share with you the link below containing a collection of photos, including a rare photo of an airplane captured and with USAAF markings, of the Japanese fighter Kawasaki Ki-100, recognized by many as one of the best, if not the best Japanese fighter designed and built during WW2. Does Ki-100 deserves the fame? What do you think? Visit the link below, see the photos and give your opinion. I hope you enjoy.


Aviação em Floripa: Kawasaki Ki-100



Cheers.

 

[cherry blossom]

There are some pictures from Britain at Cosford RAF Cosford Ki-100-IB which are better than my own efforts (but I can confirm it was still there last summer).
ps. Other sets Ki-100 Walkaround and Graham_Causer Ki-100

 

[cherry blossom]

I don't think that the performance of the Ki-100 was exceptional. I think that the reason that it was well regarded by IJA pilots was that its engines were more reliable than those of the Ki-84, which was much faster, and much more reliable than those of the Ki-61-II-kai, which was also slightly faster. The undercarriage of the Ki-84 could also give its pilots unpleasant surprises.

If we ask how fast the Ki-100 was, we end in the normal problems with Japanese aircraft. There is a thread here at http://www.ww2aircraft.net/forum/flight-test-data/ki-100-peformance-30338.html and another at J-aircraft Ki 100 Performance. My take would be that the Wikipedia speed of 580 km/h (313 kn, 360 mph) at 6,000 m (19,700 ft) would be at military power. The Ha-112-II used water/alcohol for take off and gave 1500 hp against a military 1350 hp at 2000 m. Unfortunately, I don't know if the supercharger could give you higher boost at around 6000 m. If it could, then a WEP speed should be available for a short time.

 

[kool kitty89]

The better power output of the Ki-100 over the Ki-61 should mean better climb and acceleration at low to medium speeds but weaker high speed acceleration (probably most notably in dives).

 

[GregP]

The plane in US marking is a Ki-84, not a Ki-100.

The Ki-100 was one of the 2 or 3 best Japanese fighters and was a dangerous opponent for any opponent right up to the end of the war. It was not a fast as some of the allied fighters but if they were unlucky enough to catch one or several flown by decent Japanese pilots, they were in for a scrap.

It climbed about like most Allied fighters or close enough for climb not to be a major factor, was more maneuverable than most, and had decent armament.

The two biggest weaknesses were top speed and lack of a good high-atitude supercharger.

But within it's decent altitude range it was quite good, according to everything I have read about it anyway. While there may be some, I have seen zero bad writeups on the Ki-100 by Allied or Japanese pilots. You can't say that about many Japanese fighters.
I think their three best were the J2M, Ki-100, and Ki-84 ... in no particular order. They made 3,500 Ki-84s, 543 J2Ms, and only 395 Ki-100s, so the Ki-100 was easily the rarest of the three birds above to be seen. That does not make it any less good, but it did limit the combat record.

If they aren't there, they can't make a difference.

 

[Jabberwocky]

I don't think that the performance of the Ki-100 was exceptional. I think that the reason that it was well regarded by IJA pilots was that its engines were more reliable than those of the Ki-84, which was much faster, and much more reliable than those of the Ki-61-II-kai, which was also slightly faster. The undercarriage of the Ki-84 could also give its pilots unpleasant surprises.

If we ask how fast the Ki-100 was, we end in the normal problems with Japanese aircraft. There is a thread here at http://www.ww2aircraft.net/forum/flight-test-data/ki-100-peformance-30338.html and another at J-aircraft Ki 100 Performance. My take would be that the Wikipedia speed of 580 km/h (313 kn, 360 mph) at 6,000 m (19,700 ft) would be at military power. The Ha-112-II used water/alcohol for take off and gave 1500 hp against a military 1350 hp at 2000 m. Unfortunately, I don't know if the supercharger could give you higher boost at around 6000 m. If it could, then a WEP speed should be available for a short time.

While the level speed was never eye opening, the aerobatic performance of the Ki-100 was something of a revelation, according to the few pilot accounts around.

Several translated accounts I have seen label it as the best Japanese aircraft of the war. There are a number of contributing factors to this.

The aircraft was apparently a delight to fly, across the speed and altitude range. It could be effortlessly aerobatted, with light controls and very little directional instability. This made it a good gun platform and also useful for high speed attacks against B-29s at high altitudes.

The engine and its installation were considered reliable - a not to be underestimated point for the Japanese from early 1945 onwards.

The performance - somwhere between 360 mph and 380 mph best speed at altitude - was not drastically inferior to the fastest Japanese fighters and was close to the most numerous US opponent, the F6F.

The horizontal turn performance and sustained climb performance - two qualities highly valued by Japanese aviators - were probably better than anything in the Japanese arsenal. In a level turning fight or slow speed climbing fight, the Ki-100 was judged as always superior to a Ki-84, capable of handling two Ki-84s and able to work a 1 vs 3 situation to its favour.

The aircraft was also rugged enough to be dived away at high speed. This was again important when combating B-29s and their escorts.

 

[Just Schmidt]

While not about to claim that the Ki-100 was THE best Japanese fighter, I do agree that it was one of the best. And if one rates reliability over the performance that can be expected under rare best circumstances, it might even have been the best.

As indicared abowe top speed was probably the weak point. Not only was it the slowest fighter then in Production (excepting A6M5, and though I'm thinking japan it may go for most of the world in 45), in top speed it added nothing to the Ki-61 entering service in 42. In contrast to most other Japanese late war fighters, it couldn't outrun the F6F. Given speeds are Ki 100-Otsu): 510 kmph at 1000 meters, 567 at 5000, 580 at 6000, 570 at 80000 and 535 at 10 000.

On the other hand it climbed better than its pregenitors, and in comparison with a captured P-51C it showed better diving characteristics. As most other Japanese fighters it also was considered more manouverable. But i Guess we all know by now that manouverable is a quite loose term.

It was build in fewer numbers than the J2M, but arguably made as much impact as it was concieved and produced in a remarkably short time. deliveries were 1945 march 36, april 86, may 131+(5), june 18+(78), july (26), august (10). Numbers in paranthesis are entirely newbuild aircraft instead of modified Ki 61 II airframes (Ki 100-Ko), featuring tear drop canopies (Ki 100-Otsu). Production was severely affected byB-29 bombings.

Edit: sometimes my eights are changed to smilies. I have no success changing that afterwards.

The Ki 100 was pleasant to fly even for inexperienced pilots. In the hands of vetarans, like the 244th sentai, it proved a match in fighter vs fighter engagements. On the other hand the rookies in 111th sentai suffered badly, its qualities apart it wasn't the miracle that japan was in need of.

Turbo-supercharged prototypes were flown in the hope of improving performance over 7000 meters. It's questionable how long it would have taken to get these to function reliably.

All neatly demonstrates the Japanese problem during most of the war, that in general the awailable engines didn't produce enough Power, or they didn't do it reliably enough. And while the Ki 100 never could achieve a hands down best in its category (as the H8K could), it WAS the best fighter as long as reliability is weighed heavily enough amongst the different parameters that we allways have such a hard time agreeing on. But as seen, its speed for intercepting high flying B-29s was insufficient. It was with most Japanese fighters, only 34 of the high attitude J2M5 was produced, and I have no knowledge how well the 3 stage supercharger of that worked.

My best source on the Kawasaki fighters is: William Green and Gordon Swanborough: "Japanese Army Fighters; part One", Macdonald and Janes 1976, from which I have qouted all exact figures on the Ki 100 abowe.

 

[Shortround6]

For the smilies try putting a blank space between the 8 and ).

8 ) vs 8)

 

[tomo pauk]

...
It climbed about like most Allied fighters or close enough for climb not to be a major factor, was more maneuverable than most, and had decent armament.

The two biggest weaknesses were top speed and lack of a good high-atitude supercharger.

But within it's decent altitude range it was quite good, according to everything I have read about it anyway. While there may be some, I have seen zero bad writeups on the Ki-100 by Allied or Japanese pilots. You can't say that about many Japanese fighters.
...

+1 on this.

While the level speed was never eye opening, the aerobatic performance of the Ki-100 was something of a revelation, according to the few pilot accounts around.
Several translated accounts I have seen label it as the best Japanese aircraft of the war. There are a number of contributing factors to this.
The aircraft was apparently a delight to fly, across the speed and altitude range. It could be effortlessly aerobatted, with light controls and very little directional instability. This made it a good gun platform and also useful for high speed attacks against B-29s at high altitudes.
The engine and its installation were considered reliable - a not to be underestimated point for the Japanese from early 1945 onwards.

The performance - somwhere between 360 mph and 380 mph best speed at altitude - was not drastically inferior to the fastest Japanese fighters and was close to the most numerous US opponent, the F6F.

Agreed with upper paragraph.
There is a caveat for the last paragraph, though - the US was, in 1945, using the P-51B-K, P-47D/N, P-38L, F4U-1 -4 - all of those put together make much more than Hellcat alone, and present adversaries that have from 30-90 mph advantage vs. the Ki-100, even if we assume the 380 mph mark as real.

The horizontal turn performance and sustained climb performance - two qualities highly valued by Japanese aviators - were probably better than anything in the Japanese arsenal. In a level turning fight or slow speed climbing fight, the Ki-100 was judged as always superior to a Ki-84, capable of handling two Ki-84s and able to work a 1 vs 3 situation to its favour.

That is a problem - no Allied pilot will play to the strengths of Japanese fighters so late in war, and Ki 100 represents a 'better Zero' in this regard. If possible in any way - boom and zoom.

...
On the other hand it climbed better than its pregenitors, and in comparison with a captured P-51C it showed better diving characteristics. As most other Japanese fighters it also was considered more manouverable. But i Guess we all know by now that manouverable is a quite loose term.

Claim that Ki 100 was a better diver than P-51C should raise an eyebrow - maybe you could shed some light on that?

Turbo-supercharged prototypes were flown in the hope of improving performance over 7000 meters. It's questionable how long it would have taken to get these to function reliably.

It was with most Japanese fighters, only 34 of the high attitude J2M5 was produced, and I have no knowledge how well the 3 stage supercharger of that worked.

I'd also would ask you to share some good information on turboed Ki 100, also on the 3-stage superchargers for the Kasei.

 

[kool kitty89]

Claim that Ki 100 was a better diver than P-51C should raise an eyebrow - maybe you could shed some light on that?

At a guess, I'd think it would be somewhat like the P-36/Hawk 75 compared to the Spitfire I or 109E, with slower dive acceleration but better control characteristics at high speed.

 

[Shortround6]

Not all radial engine installations were the same, the Japanese had 6 years to figure out a better radial installation than the P-36/Hawk 75 used.

From a 1946 flight article, something of a crude generalization (compressability NOT taken into account)

http://www.wwiiaircraftperformance.org/wade-dive.jpg

Note Tempest II and Tempest V

 

[Just Schmidt]

I'd also would ask you to share some good information on turboed Ki 100, also on the 3-stage superchargers for the Kasei.

As for the diving test and mock up combat, I can add only that it took place at Yokota. I can speculate that unfamiliarity with the P-51 on the part of the pilot, state of maintenance and Japanese fuel played a role. Also, from the zoom thread we know that meassurig diving isn't a one-parameter excercise. The diving speed of the Ki-100 I is stated as 850 kmh (actually the first half of the first link shared in #3 is scanned from the Swanborough/Green book, also giving numbers on performance of the turbosupercherged Ki-100 II).

"The turbine was placed beneth the engine and the supercharger installation was similar to that previously utilised by the Ki 102-Ko and calling only forthe relocation of of some fuel lines and accessories, and transfer of the centrally-located ventral air scoop to starboard. Space restrictions prohibited the installation of an intercooler and associated ducting, and air was fed directly from compressor to the carburettor. Designated Ki 100-II, the first of three prototypes to be fitted With the Ru-102 turbo-supercharger was completed within six weeks of design work commencing. Flying in May 1945, the second and Third prototypes following at fortnightly intervals. Although the lack of intercooler restricted the high altitude performance of the Ki 100-II, the turbosupercharger-equipped fighter displayed a noteworthy improvement over the Ki 100_I, although the hand-made joints in the exhaust collector ring suffered excessive leakage with the result that the rated attitude of each prototype differed under test. Kawasaki had been instructed to use A1 coated carbon steel for the exhaust system, but this was considered to have been a mistake and alternative materials were under consideration when hostilities came to an end..."

Ki 102-Ko Autumn 44: "its Production phase-in was was impractical owing to development problems being encountered with the exhaust driven turbo-superchargers. Mounted in the end of the engine nacelles, the Ru-102 turbo-superchargers enabled the Ha-112-II Ru engines to maintain their rated Power of 1.250 hp up 10 26.900 ft ( 8200 m)..." It goes on to descripe how, on 1st November, a test flight by Major Yasuhiko Kuroe resulted in an attemted interception of a B-29 over Tokyo, which was aborted after both turbo-superchargers failed. The Ko was developed into the Ki 108, adding yet more complications with a pressure cabin. Only 2 prototypes were build.

(William Green and Gordon Swanborough: "Japanese Army Fighters; part One", Macdonald and Janes 1976).

Unfortunately I can add very little about the engine of the J2M5, I was kind of fishing for more information here, perhaps from one of our Japanese members. The engine is the MK4U-4 Kasei 26a. (Elke C. Weal (ed): "Combat Aircraft of world war two"Bracken Books 1985) It cites a top speed of 615 kmh at 6800 meters. I've found it to be a quite solid reference work. though in covering thousands of types some typos inevitably sneak in. And on especially the russian types, it is sometimes clear that detailed reliable data are lacking (as those given are often quite sparse). That it somewhat unusually has s seperate entry for the J2M5 (besides for J2M3), makes me suspect there are some good numbers out there somewhere. Elsewhere I've seen the loose assertions of the Kasei 26a as a much better engine (than the Kasei 23a), but that is rather vague. Please don't ask me to elaborate on that.

 

[Gnomey]

Good stuff! Thanks for sharing.

 

[Wayne Little]

Good series of shots..

 

[Jabberwocky]

There is a caveat for the last paragraph, though - the US was, in 1945, using the P-51B-K, P-47D/N, P-38L, F4U-1 -4 - all of those put together make much more than Hellcat alone, and present adversaries that have from 30-90 mph advantage vs. the Ki-100, even if we assume the 380 mph mark as real.

I agree that those fighters have significant performance advantages over the F6F-3/-5. I don't agree that all these fighters combined were more likely to run into a Ki-100.

If you look at the aerial claims in theatres against the Japanese, there are some interesting statistics as to which aircraft actually shot down the most Japanese planes.

The F6F made its combat debut in September 1943. Between then and the end of the war, it claimed either 5156 or 5168 Japanese aircraft in aerial combat (stats differ a little) with the USN and the Marine Corps.

From September 1943, all other USAAF and USN fighter aircraft claimed a combined total of 5624 Japanese aircraft in aerial combat.

So, by my possibly dodgy math, that means that from the time it entered combat to the end of the Pacific war, the F6F accounted for 48% of all aerial claims by fighters against the Japanese.

 

[Juha]

I agree that those fighters have significant performance advantages over the F6F-3/-5. I don't agree that all these fighters combined were more likely to run into a Ki-100.

If you look at the aerial claims in theatres against the Japanese, there are some interesting statistics as to which aircraft actually shot down the most Japanese planes.

The F6F made its combat debut in September 1943. Between then and the end of the war, it claimed either 5156 or 5168 Japanese aircraft in aerial combat (stats differ a little) with the USN and the Marine Corps.

From September 1943, all other USAAF and USN fighter aircraft claimed a combined total of 5624 Japanese aircraft in aerial combat.

So, by my possibly dodgy math, that means that from the time it entered combat to the end of the Pacific war, the F6F accounted for 48% of all aerial claims by fighters against the Japanese.

Yes, but Ki-100s operated over Japan only from Spring 45 onwards and I guess that vast majority of F6F pilots' claims were earlier and from other areas when e.g. significant portion of P-51 pilots' claims were made over Japan. And F4U became the dominant carrier fighter around the same time when Ki-100 appeared.

 

[Ottobon]

Even if you are aware that Japanese aircraft were only tested at Military power rather then WEP by Japan, and that the true top speed of the Ki-100 is probably greater then 360mph, i think its obvious that the Ki-84 which could do about 430mph (utilizing War Emergency Power) and the J2M5 which i believe was also close to that were superior fighters by western standards.

However, what makes the Ki-100 outstanding is that it was a reliable, tough, easy to fly aircraft and without complicated manufacturing. If it would of ever been used in large numbers was more then good enough to do its job against say F6Fs or probably F4U-1D. It also fit the mentality of Japanese pilots who desired great maneuverability, which is probably where the Japanese story comes from that in tests it could take on 3 Ki-84s which honestly seems like a insane claim, but probably just demonstrate how they preferred to fight and what they were most comfortable in, if not that then maybe (?) unreliability of the Homare-45 engine of the Hayate.

Even if it wasn't really perfect match against a competent pilot in say a F4U-4 or similarly amazing end-war aircraft it could have encountered i don't think that makes it less great as in the real world there is huge value in a reliable, simple, easy to fly aircraft that one could potential field in great numbers.


If the He 162 was a horrible example of a (potentially) mass produced emergency fighter for novice pilots, the Ki-100 was a brilliant one.

 

[GregP]

Interesting post, Ottobon. The He 162 is a bad axample and was lethal to non-veteran pilots.

 

[Shortround6]

True but it points to what both the Japanese and Germans needed late in the war. Not just better performing fighters but fighters that didn't require highly skilled pilots to use them. Planes that were forgiving in both landing and flight characteristics and yet had enough performance not to be sitting ducks for the enemy. A 360-380mph airplane that was easy to fly beats the heck out of both a 330mph airplane that is super easy to fly or a 410mph plane that was tricky and unforgiving to fly and land.

 

[kool kitty89]

True but it points to what both the Japanese and Germans needed late in the war. Not just better performing fighters but fighters that didn't require highly skilled pilots to use them. Planes that were forgiving in both landing and flight characteristics and yet had enough performance not to be sitting ducks for the enemy. A 360-380mph airplane that was easy to fly beats the heck out of both a 330mph airplane that is super easy to fly or a 410mph plane that was tricky and unforgiving to fly and land.

The Bf 109 shared some of those same problems throughout the war ... the emergency fighter program in Germany was a bad (proposed) solution to a larger set of problems that had present to some degree from the start of the war with their problematic pilot training infrastructure and Bf 109 as the mainstay fighter. (the aging 109 airframe with its limitations -even heavily refined into the 109F- in range/endurance, cockpit visibility, and handling -especially on the ground)